Flexible coupling for radio volume control or the like



Nov. 23, 1937. G. J. BARRY 2,100,232

FLEXIBLE COUPLING FOR RADIO VOLUME CONTROL OR THE LIKE Filed May 19, 1936 Patented Nov. 23, 1937 UNITED STATES PATENT OFFICE FLEXIBLE COUPLING FOR RADIO VOLUME CONTROL OR THE LIKE Application May 19, 1936, Serial No. 80,630

3 Claims.

This invention relates to flexible shaft coupling devices and, more particularly, to a novel flexible shaft coupling for a volume control device of a radio receiver. It is frequently desirable to mount the volume control device of a radio receiver at the rear of the receiver chassis or at least at some position removed from the front part of the chassis. This requires that the control shaft for the volume control device extend 0 forwardly of the chassis through a support on the chassis and through the control panel of the radio cabinet. In view of the slight inaccuracies or misalignments of parts which are bound to occur in present day production methods, it is necessary that the control shaft be provided with a flexible coupling to permit slight axial misalignment of two shaft members in order that the forward end of the shaft may be brought through the front chassis support and the control panel and in order that the shaft may be freely operated to actuate the volume control device. It is desirable, however, that angular movement of the shaft members relative to one another be prevented in order that the turning of one shaft 25 member will turn the other shaft member accordingly. Moreover, the control shaft is commonly grounded at the volume control device, and as it is desirable to have the entire shaft grounded,

a good electrical jointshould be provided at the to provide a novel coupling having these desirable characteristics and which is adapted for the specific purpose in view.

A more specific object of the invention is to provide a novel coupling employing in combination with interlockable shaft members a resilient spring member arranged cooperatively with the shaft members and imparting to the device the features and desirable characteristics above set forth.

Other objects and features of the invention will appear hereinafter.

In the accompanying drawing:

Fig. l is a sectional elevation showing the disposition of a volume control device at a point removed from the front of the chassis and showing the novel coupling of the invention employed in connection therewith;

Fig. 2 is an enlarged fragmentary view showing a portion of the coupling in section for the purpose of illustration;

Fig. 3 is a similar view with the shaft rotated through 90 from its position in Fig. 2;

Fig. 4 is a fragmentary perspective view of one of the shaft members embodying one of the coupling parts;

Fig. 5 is a similar view of the other shaft member embodying another of the coupling parts; and 5 Fig. 6 is a perspective view of the resilient spring member employed in cooperative association with the coupling parts of Figs. 4 and 5.

Referring to Fig. 1, a volume control device of conventional form is shown at I and this device is mounted on a portion of the chassis 2 remote from the front of the chassis by means of a supporting bracket 3. The control shaft for the volume control device is shown generally at 4 and extends forwardly of the chassis through a front wall 5 of the chassis. Suitable means for retaining the front end of the shaft on the supporting wall 5 and for preventing axial movement of the shaft is shown at 6. Such means may comprise a washer l and a. circular key 8 cooperatively as sociated with the shaft on each side of the wall 5. As above stated, it is frequently desired to thus mount a volume control device for a radio receiver and it is necessary to provide some flexible shaft coupling. The coupling of the present invention is designated generally by numeral 9 in Fig. 1 and is preferably disposed near the volume control device I as illustrated.

Heretofore, a flexible shaft coupling device of conventional form has been employed, such coupling simply comprising two shaft members with interlocked ends. Such a coupling isinherently objectionable and unsatisfactory for the specific purpose here involved for the reason that it lacks the features or characteristics above mentioned. More specifically, if the interlocked coupling members of such a device are formed so as to fit snugly and thus eliminate angular play between them, the desired and necessary misalignability of the axes of the shaft members is prevented. Furthermore, it is impossible to obtain a good electrical joint by merely employing two interlocked coupling members. On the other hand, if the coupling members are made slightly loose fitting to provide the necessary misalignability of the axes of the shaft members, there results unobjectionable angular play between the shaft members and, furthermore, a very poor electrical joint is obtained. Thus, the design of such a coupling to embody one desirable or necessary feature is effected at a sacrifice of another desirable or necessary feature.

In accordance with the present invention, one of the shaft members 4a is provided with a noncircular part'preferably in the form of a flat ex- 5 tension or part in, as shown clearly in Fig. 4, while the other shaft member 41) is bifurcated to provide a corresponding recess or slot I I adapted to receive the part ill. The recess or slot II is slightly wider than the part It! so that the two coupling parts are loose fitting. A pin-like projection I2 is provided on part It] and a corresponding recess i3 is provided in the other shaft member 422 adjacent the recess H so as to receive the pin as shown clearly in Figs. 2 and 3.

A resilient spring member [4 which preferably consists of a piece of flat spring metal bent in the form of a U (see Fig. 6) is adapted to fit over the flat part II), as shown in Fig. 3, and is provided with an aperture I through which the projection l2 may extend. The spring member is also adapted to seat within the recess l l, as shown clearly in Fig. 3. It will be seen that the opposed sides of the spring member are flexible and take up the space and play between the part It] and the bifurcated end of the shaft member 4b. Therefore angular movement of one shaft member causes corresponding angular movement of during such movement the opposed sides of the the other shaft member. Furthermore, the resilient spring member permits slight misalignment of the axes of the shaft members which is desirable and necessary for the reasons above stated. In other words, as will-be seen from Fig. 3, the shaft members may be moved relatively to one another in the plane of the paper and spring member will flex slightly, providing a sort of resilient connection between the two shaft members. The spring member also snugly engages the coupling parts at-all times so that a good electrical joint is maintained between the shaft members, thus grounding the entire control "shaft, as above mentioned.

With the parts in assembled relation, as shown in Figs. 2 and 3, the projection I2 locks the spring member M in place on the flat part In and the seating of the projection l2 in recess l3 locks the shaft members together. It will be apparent that the parts are of simple construction and may be easily assembled. Hence the device may be manufactured and assembled at low cost.

The invention contemplates broadly the provision of loosely fitted coupling members and resilient means cooperatively associated with said members to perform the several functions above stated. It will be understood, therefore, that the invention is not limited to the specific form of the device illustrated and that various changes and modifications, particularly as to the: details of the device, may be made while still conforming to the principles of the invention.

I claim:

1. A flexible shaft coupling for a radio volume control or the like, comprising a pair of electrically-conductive members having interlocking portions forming a flexible joint, one of said portions comprising a non-circular part and a projection extending therefrom, the other of said portions having anon-circular recess to receive said part and another recess to receive said projection, and an electrically-conductive resilient spring extending about said part and having an aperture through which said projection extends, for preventing angular movement of said members relative to one another while permitting axial misalignment of said members, and for forming a good electrical joint between said members, said projection serving to hold said spring in place and cooperating with said other recess to interlock said members.

2. A flexible shaft coupling for a radio volume control or the like, comprising a pair of electrically-conductive members having interlocking portions forming a flexible joint, one of said portions comprising a flat part and a projection extending therefrom, the other of said portions having a slot to receive said part and a recess to receive said projection, and an electricallyconductive resilient spring extending about said part and having an aperture through which said projection extends, for preventing angular movement of said members relative to one another while permitting axial misalignment of said members, and for forming a good electrical joint between said members, said projection serving to hold said spring in place and cooperating with said other recess to interlock said members.

3. A flexible coupling, comprising a pair of shaft members having cooperatively associated end portions forming a flexible joint, one of said end portions being bifurcated to provide a slot at its end and having a recess'extending axially from said slot, the other of said end portions having a flat extending part seated in said slot and a projection extending axially from said part into said recess, and a U-shaped spring member formed of fiat spring metal extending about the end of said flat part and having an aperture through which said projection extends, whereby said spring member is held in place and said shaft members are interlocked with one another, said spring member having bowed resilient sides interposed between the sides of said flat part and the sides of saidslot for taking up the play between said end portions while permitting axial misalignment of the shaft members. a

GERALD J. BARRY. 

